In this work we use the so-called `observers convention' which defines position angles as increasing counter-clockwise on the sky. This means that when the slope of the PA traverse is positive then the sign of \(\beta \)  is negative. Also, when \(\alpha < 90\)  and \(\beta > 0\)  then we observe an outer line of sight (i.e. away from the spin axis and towards the equator). However, for \(\alpha > 90\)  and \(\beta > 0\)  we observe an inner line of sight (i.e. nearer to the spin axis). Therefore the sign of \(\beta \)  alone does not reveal whether the sight line is inner or outer. For a detailed discussion see [1]}.
